The present invention relates to surgical cutting and surgical cutting instruments. More particularly, aspects relate to surgical cutting instruments and systems capable of both high-speed cutting and, in some embodiments electrical probing or evoked potential monitoring functions, as well as procedures utilizing such a device.
Surgical cutting instruments are commonly used to perform a variety of procedures. For example, many neurotological surgical operations involve partial or total removal of bone or other hard tissue via a high-speed rotating bur or other cutting tips. Exemplary procedures in this field include cochleostomies, removal of acoustic neuroma tumors, and removal of the scutum in a tympanoplasty. Numerous other surgical operations have similar bone/hard tissue cutting or removal requirements. The typical surgical cutting instrument is akin to a drill, including a drill handpiece that rotates a cutting implement. The handpiece houses a motor and a chuck or other adapter, with the chuck being rotated by the motor under the control of a foot-operated or finger-operated switch.
Human nerves are often in close proximity to an area of bone or tissue removal in many surgical procedures. Thus, one overarching concern relating to these types of surgical cutting operations and instruments is the danger of severing or otherwise damaging nerves through inadvertent cutting or excessive heat. For example, when a straight bur cutting instrument is used for bulk bone removal, a surgeon might be concerned with over-aggressive cutting as well as wobble and associated nerve damage. As another example, a curved bur cutting instrument used in finer cutting applications might have a high thermal discharge at the cutting bur giving rise to nerve damage concerns.
Indeed, often times the above-described surgical cutting instruments require additional steps and instruments for measuring nerve location to complete a surgical procedure. For example, a mastoidectomy can entail exposing the mastoidperiostiem and then carefully drilling/removing the mastoid bone using a cutting instrument and microscope. Moreover, a patient may have abnormal anatomy due to congenital or iatrogenic defects that places nerves in unanticipated regions such that the anatomical landmarks a surgeon might otherwise normally refer to as a guide for neural tissue may not exist. While carrying out such procedures, a surgeon can be required to sequentially cut with a surgical cutting instrument and then probe a cut area for nerves with a separate evoked potential monitoring system handpiece. This is clearly time-consuming and thus undesirable.